In the production of oil and/or gas, in addition to the production of the desired fluid, sometimes a heavier fluid is produced. These heavier fluids must be separated from the oil and gas and disposed of.
Preferably, the undesired heavier fluids are separated from the desired fluids downhole and are injected into a disposal formation without being brought to ground surface. Where the disposal formation is located above the production formation, an uphole injection tool is required to be used to effect such downhole separation.
An uphole injection tool is disclosed in U.S. Pat. No. 5,579,838 of Michael. The tool which is disclosed handles the lighter fluids and heavier fluids separately after they have been separated by residence time downhole. The tool includes an assembly having a first conduit for movement of heavy fluids and a second conduit for movement of lighter fluids. A pump is provided for moving the heavier fluids. The first conduit opens via a plurality of ports into a disposal formation for injection of the heavier fluids thereto.
The tool of Michael has limited use however as the ports to the disposal formation are permanently open. These ports prevent isolation of the disposal formation from the production formation and limit selective access to the production formation by some tools and by fluids injected from the surface.
An uphole injection tool is required that can also be used to selectively isolate the disposal zone from the other zones.